Dynamics of fractionalized mean-field theories: Consequences for Kitaev materials
Dynamics of fractionalized mean-field theories: Consequences for Kitaev materials
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DOI：
10.1103/physrevb.107.224428
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发表时间：
2022-06
影响因子：
3.7
通讯作者：
Tessa Cookmeyer;J. Moore
中科院分区：
文献类型：
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作者：
Tessa Cookmeyer;J. Moore
最近有大量的努力，实验和理论上，找到一个物质实现的Kitaev自旋液体-基态的精确可解Kitaev模型的蜂窝晶格。候选材料现在很丰富，但非Kitaev条款的存在使得理论和实验之间的比较具有挑战性。我们重新推导时间相关的马约拉纳平均场理论，并将其扩展到包括量子相位信息，允许直接计算实验相关的动态自旋-自旋相关器，再现未扰动模型的精确结果。在以前的工作相比，我们发现，小扰动并没有实质性地改变确切的结果，这意味着，$\alpha$-RuCl${}_3$可能是远离Kitaev阶段比原来认为的。我们的方法推广到任何相关器和任何模型，马约拉纳平均场理论是一个有效的起点。
There have been substantial recent efforts, both experimentally and theoretically, to find a material realization of the Kitaev spin-liquid--the ground state of the exactly solvable Kitaev model on the honeycomb lattice. Candidate materials are now plentiful, but the presence of non-Kitaev terms makes comparison between theory and experiment challenging. We rederive time-dependent Majorana mean-field theory and extend it to include quantum phase information, allowing the direct computation of the experimentally relevant dynamical spin-spin correlator, which reproduces exact results for the unperturbed model. In contrast to previous work, we find that small perturbations do not substantially alter the exact result, implying that $\alpha$-RuCl${}_3$ is perhaps farther from the Kitaev phase than originally thought. Our approach generalizes to any correlator and to any model where Majorana mean-field theory is a valid starting point.